This invention is directed generally to methods and apparatus useful in pouring of concrete decks and, more particularly, to the methods and apparatus for forming and supporting poured concrete decks.
When pouring a concrete deck that is spaced above an underlying floor, such as in multi-level buildings or concrete houses, a deck forming system must be erected to form and support the poured concrete until it has cured to a preselected strength. A typical deck forming system uses a grid formed from interconnected deck beams that are supported at the desired height by a plurality of spaced apart and vertically adjustable jack posts. The open areas in the grid are completely filled by a plurality of appropriately sized flat panels that extend horizontally between the deck beams. The deck panels are removably secured to the deck beams by suitable fasteners. One commonly used fastener utilizes a pin that extends through aligned holes in the ends of the panels and sides of the beams and is retained in place by a wedge that extends through a closed-end slot in the pin. The resulting deck forming system provides an uninterrupted, horizontal, upper surface onto which the concrete is poured to form the deck.
After pouring concrete decks, it is normally necessary to leave the jack posts in place for an extended period of time to support the concrete deck while the concrete achieves the strength necessary to span the distance between the supporting walls. Jack post support is particularly needed when the deck must also support the load of one or more overlying decks that are being sequentially formed and poured. Although the jack posts must normally be left in place for an extended period of time, the deck panels and beams can be removed more quickly and it is often desirable to remove these components as soon as possible so that they can be used to form other concrete decks. In order to facilitate removal of these components while leaving the jack post in place, it is known to use a drop head assembly to removably connect the jack post to the grid beams. These drop heads use a header having a flat upper surface which serves as a partial form for the concrete deck and a cross member that is carried on a second screw on the jack post. The cross member can support up to four deck beams and has upstanding retaining pins that are received in complementally positioned holes formed in the beams. The cross member can be vertically adjusted by turning the second screw to bring the top surface of the beams in horizontal alignment with the top surface of the header during erection of the grid. After the deck has been poured and has sufficiently hardened, the cross member can be lowered by turning the second screw in the opposite direction to provide sufficient vertical clearance to allow removal of the deck panels and to permit the deck beams to be lifted off the cross member. The header remains in place supporting the concrete deck and can be removed with the jack post by turning the first screw to shorten the height of the jack post.
While the drop head assembly described above allows the deck panels and grid beams to be xe2x80x9cstrippedxe2x80x9d or removed while the jack post remains in place, erection of the grid can be cumbersome and time-consuming because of the need to adjust the height of the jack screw using the first screw followed by adjusting the second screw to raise the cross member and beams to the desired height. Removal of the grid is also time-consuming because the cross member must first be lowered sufficiently to provide the vertical clearance needed to lift the beams off of the retaining pins carried by the cross member. The use of the cross member and the attendant need for a second screw also increases the cost and weight of the drop head assembly.
A need has thus developed for a lighter and less expensive jack post assembly that allows the deck forming grid to be more easily and quickly erected and disassembled.
In one aspect, the present invention is directed to an apparatus for use in forming and supporting a poured concrete deck. The apparatus comprises: a header having opposed ends and a center support which carries a generally flat first forming plate at an upper end thereof, the header further comprising downwardly extending first mounting brackets positioned at opposite sides of the forming plate for releaseably holding deck panels on which the concrete deck is poured; at least one beam having opposed ends and positionable in longitudinal alignment with the header, the beam having a center support which carries a generally flat second forming plate at an upper end thereof and downwardly extending second mounting brackets positioned at opposite sides of the second to forming plate for releaseably holding said deck panels; a connector for extending along and releaseably joining the center support of the header with the center support of the beam; and a post coupled with said header for supporting said header and said at least one beam at a preselected height. Notably, the connector eliminates the need for the cross member and second screw used in conventional drop head assemblies, thereby providing weight and cost savings and facilitating the ease with which the apparatus may be erected and disassembled.
In another aspect, the present invention is directed to a method of pouring and supporting the concrete deck using the apparatus described above. In the method, a form for receiving and supporting poured concrete is prepared by: joining at least one beam to a header in longitudinal alignment using a connector releaseably connected to center supports of the beam and the header; supporting the header and beam on a post at a preselected height; and releaseably joining at least one deck panel to the joined beam and header. A layer of concrete is then poured on an upper surface of the deck panel and an upper surface of said header while the deck panel is joined with said beam and header. After the concrete has hardened to a preselected strength, the deck panels are removed from the joined beam and header and the beam is then removed from the header by disconnecting the connecter from the center supports of the beam and header. The post and header are then left in place to support the hardened layer of concrete for a preselected period of time after the beam has been removed. The post and header can then be removed and reused.